EMT (Electro-metallic tubing) is generally used in pipe-framed fences. This is the solid-wall conduit that electricians use, generally 1.5 to 3 inch diameter.
We usually don't find nickel pipes, as in pipes made of nickel metal. We do find that nickel is added to other metal(s) to make an alloy that can be used to make different kinds of pipe. Nickel is...